Sheet feeder



Feb. 2, 1943. H. A. PRlTCHARD SHEET FEEDER 2 Sheets-Shet 1 Filed May 8,1940 A INVENTOR. f/ovmeo ,9. "Pena/M20 MW W ATTORNEYfi Feb. 1943.. H, A.PRITCHARD H 2,309,979

' SHEET FEEDER Filed May 8. 1940 2 Sheets-Sheet 2 INVENTOR. Hoomeo A!Pare/men Y 12% f/wm 1K ATTORNIzlYfi Patented Feb. 2, 1943 OFFICE SHEETFEEDER Howard A. Pritchard, Hiram, Ohio, assignor toHarris-Seybold-Potter Company, Cleveland, Ohio, a corporation ofDelaware Application May 8, 1940, Serial No. 334,013

20 Claims.

This invention relates to sheet feeders for printing presses or othersheet handling machines and has particular reference to mechanism inwhich the sheets are forwarded in lapped formation to a position'of restfrom which they are taken into the machine by a variable speed transfermechanism. The invention provides means whereby the variable motion ofsuch a transfer mechanism is utilized to determine or to control thespeed of the foremost lapped sheet as it approaches its position ofrest.

When sheets are advanced in the conventional manner to a position ofrest against front registering stops there is danger of the front edgebuckling or rebounding at the stops so that an out of register conditionis obtained. This is true even when the sheets are advanced atrelatively slow speed in the form of a stream of lapped sheets with eachsheet partly overlying the next following sheet. Furthermore, successivesheets are frequently displaced slightly forward or backward from theirdesired positions as they are conveyed toward said stops. At other timestheir front edges are not in true alignment with said stops and thesheets must be straightened.

Accordingly it is among the objects of this invention to provide meansfor accurately and gently presenting a sheet to front registering stops.

Another object is to provide mechanism of the type described whichwillserve to straighten the sheets as; they approach a position of rest.

Another object is to provide means for vary ing the speed ofpresentation of lapped sheets to a position of rest.

Another object is to provide in combination with a variably moving sheettransfer device, means for slowing down the foremost sheet of a streamof lapped sheets as the latter approaches stationary position againststops adjacent said transfer device, which means shall depend either forthe character of its movement or for its actuation upon the operation ofsaid transfer device.

Another object is to provide slowdown means which shall have speedproportional to but less than the speed of the transfer device.

Another object is to provide means for feeding sheets in lapped relationto a position of rest adjacent to a variably rotating transfer device ata speed dependent upon the variations of speed of the transfer device.

Another object is to' provide mechanism of the type described which willbe simple in construction and effective in operation.

Other objects will appear from the following description and drawings inwhich:

Figure 1 is a diagrammatic side elevational view of the pertinent partsof a sheet feeding mechanism according to the invention.

Figures 2 and 3 are detail views in different positions of one form ofthe device employing suction wheels for controlling the sheets.

Figures 4 and 5 are similar views of another form of the deviceemploying rotating slowdown stops,

Figure 6 is a view along the line 6-6 of Figure I I 4 showing means forrapidly withdrawing the rotary stops or slowdowns from the path of asheet about to be transferred, and

Figure 7 is a fragmental View, similar to Fig. 4, showing amodification.

Referring to Figure 1 the sheets to be fed to the printing or othermachine are taken from a pile ID by well known devices such as suckers Hand conveyed forward into the bite of advancing rollers I2 and I3 whichfurther advance the sheet. As illustrated, roller I3 is driven with suchspeed as to cause each sheet to be only partially withdrawn from thepile at the time the next sheet is fed between the rollers l2 and I3,thus producing a stream of lapped sheets inthe familiar manner.

Trained around roller [3 and a forwardly disposed roller I4 are tapes l5which convey the sheets toward the press. Rider rollers I6 serve to holdthe. sheets against the tapes to insure their advancement. These sheetsare conveyed to a position of rest against stops I! where they arefurther registered in the usual manner and from this position of restthey are taken by grippers 25 on a variably moving transfer device l9and transferred thereby to grippers 20 of a uniformly rotating cylinder,such as the impression cylinder 2|, of a printing or other sheethandling machine.

Referring to Figs. 2 and 3 the transfer device be employed to producethe desired rotation of the transfer device, such mechanisms being knownin the art, as for example in Harrold et al. Patent No. 2,192,908.

The transfer device is provided with grippers 25 mounted on shaft 26 allarranged in known manner to be withdrawn into the transfer devicesufficiently toppass and avoid interference with a sheet approaching thefront stops and to move outwardly and into gripping engagement with thesheet while the transfer device is stationary. Mechanism for thispurpose also is disclosed in the said Harrold 'et al. patent.

The sheets are advanced toward their position of rest over a feed board21 and into contact with the stops H which are mounted on shaft 28extending across the machine and operated in the usual manner to engagethe forward edge of a sheet at the proper time and to withdraw from thepath of the sheets when a sheet is about to be transferred to thecylinder 2|.

In the form of the invention illustrated in'Figs. 2 and 3 I provide aslot 29 in the feed board 21 to accommodate suction wheels 30, of whichthere may be two or more spaced transversely across the machine, mountedon shaft 31. These suction wheels are provided with perforations 32 intheir rims which register successively with pockets 33 in arms 34, whichpockets are connected by tubes 35 to a source of suction, wherebysuction may be intermittently produced in the pockets 33 andconsequently in the perforations 32 of the rims of the suction wheels asthe perforations register successively with the pockets 33. The arms 34may be supported in any desired manner and the usual suction producingand controlling mechanism may be connected to the tubes 35.

At a point preferably outside the frame of the machine and in suchposition as not to interfere with shaft 28 a gear 36 is secured to shaft3| and arranged to mesh with a gear 3'! secured to shaft 22 of thetransfer de'vice. By this gearing the shaft 3| and suction wheels 30 aregiven rotary movement conforming to that of the transfer device. Thus asthe I transfer device decelerates, the suction wheels 30 alsodecelerate, and as the transfer device moves at the speed imparted to itby its driving mechanism, the suction wheels partake of a movement inthe proper direction proportional to the movement of the transferdevice. The proportions of the gears 36 and 31 may be varied accordingto the result desired. For example, while I have illustrated the devicein connection with stream fed sheets it is apparent that it may beemployed with sheets fed in entirely separated condition, and in thislatter case the proportions of the gears 36 and 31 would be preferablysuch as to produce a surface speed of the suction wheels 30approximately equal to the speed of the sheets at the time the wheelsbecome effective, their speeds then decreasing to zero as the transferdevice decelerates. Preferably, however, and in connection with streamfeeding as disclosed herein, the gears 35 and 31 are so proportioned asto produce an initial surface speed of the suction wheels 30 which is afraction of the maximum speed of the transfer device and approximatelyequal to the speed of the sheets of the stream as they are conveyed bythe tapes l5.

In Fig. 2 the positionof the transfer cylinder at the stationary pointin its operation is illustrated in full lines, while its position at theend of its period of acceleration is indicated in dotted of the periodof deceleration. Between the dotted line position of Fig. 2 and theposition of Fig. 3 the transfer cylinder rotates at a constant ratewitha peripheral speed equal to that of the impression cylinder.

With the parts in the position of Fig. 3, where the transfer deviceisjust beginning to decelerate, suction is applied to the suction wheels30 so that they engage the undersurface of the foremost sheet of thestream while the suction wheels and sheets are moving at approximatelythe same speed; From this point on the transfer device decelerates tozero and the suction wheels 30 likewise decelerate to zero and as aconsequence slow down the sheet as the latter approaches the stops H.The suction is preferably cut off just before the sheet reaches thefront stops l1, and the sheet is then urged into final registeredposition against the stops by the continued forward movement of thestream.

Obviously the timing of the suction may be such that instead of itsbeing cut off slightlybefore the sheet reaches the front stops, aspreferred, it will be cut off precisely at that point or slightlythereafter. In bothof the latter cases the sheet will be under thecontrol of the suction wheels from the time they engage it until itstrikes the stops, and after the sheet is against the stops the suctionwheels may act momentarily to hold it there, dependent upon the exactmoment when the suction is terminated, and the movement of the streamfunctions also for that purpose. In any event the effect of the suctionwheels is to slow the sheets down so that they are presented gently andaccurately to the front stops.

After the sheets have been stopped and any additional registeringoperations have been performed, the grippers 25 close upon the frontedge of the sheet, and thereafter the transfer device begins toaccelerate and speeds up the sheet to the speed of the impressioncylinder and transfers the sheet to the latter cylinder, the stops IImeanwhile having been dropped out of the way of the sheets.

In the'form of device illustrated in Figs. 4 to 6 inclusive the sheetsas they approach their positions of rest are engaged by two or morerotating stops 40 keyed to a shaft M which is driven by gears 42 and 43that correspond in purpose to gears 36. and 31 in the other form of theinvention. The stops 4!] pass through slots 44 in the feed board 21 justin advance of the forward edge of the sheet, which soon thereaftercatches up with the stops. The stops then decelerate and the sheet comesto rest against them in the proper position to be taken by the grippersof the impression cylinder. These stops therefore perform the doublefunction of slowing down as well as front registering the sheets.

The gears 42 and 43 are inthis form equal in diameter so as to cause onecomplete rotation of the stops for each rotation of the transfer device,and the stops are preferably arranged at such a distance from the axisof shaft 4| that they move with a maximum peripheral speed slightly lessthan the speed of a sheet forwarded by tapes I5. Thus the stops 40 willbe engaged by a sheet shortly after the position illustrated in Fig. 5and the sheet will thereupon be slowed by the deceleration of the stopsacting against the forwarding impetus of the stream. Thus the stops willcooperate with the stream to align or straighten the sheet as well as toslow it down.

As illustrated in Fig. a series of tongues 45 may be secured to thetransfer device to cooperate with the feed board in confining theforward edge of thesheet tothe desired path.

An alternative construction is illustrated in Fig. 7 where stops ofnon-rotating character and of familiar design and operation, mounted onan oscillating shaft I28 are provided in addition to the rotating stops40. In this case the parts are so arranged that the stops 40 moveforward slightly beyond the position of stops I I1 beforetheirdecelerating motion terminates, so that the stops 40 act asslow-down means only while the front registration of the sheets iseffected against stops Thereafter stops drop below the sheet path in amanner well known in the art.

In both of the'last described forms of the invention, in order to movethe stops 4!] out of the path of the sheet when the latter has beengripped and starts forward from its stationary position, I provide adriving arrangement for the shaft 4| which permits it to be drivenmomentarily ahead of its gearing in order that the stops 40 may bewithdrawn much more rapidly than they move at other times. Thisarrangement is illustrated in Figs. 4 and 6. The gear 42 which isretained on the shaft 4| by collar 46 is loosely mounted on the shaftand is resiliently connected thereto by spring 41, one end of which issecured to the gear 42 and the other end to a collar 48 which is keyedto the shaft 4|. Collar 48 carries a fixed stud 49 and the gear42carries a pin 5|) which provide a positive drive between the gear andthe shaft, the spring 41 providing a resilient connection which permitsthe shaft to rotate faster than the gear momentarily. Inside the frame Fof the machine is a crank arm 5| keyed to shaft 4|, which crank armcarries a roller 52. A cam 53 is secured by bolts 54 to the transfermember disk 23. Cam 53 and roller 52 are so positioned as to be insubstantial contact at the time the stops 40 are stationary so that asthe transfer member begins to rotate after taking a sheet the cam 53operates through the roller 52 and crank 5| to turn the shaft 4| aheadof its gear drive at a speed sufiicient to quickly carry the stops 4|]out of the path of the advancing sheet so as not to interfere with theforwarding of the latter.

It will be apparent that the invention may, if desired, be utilized toslow down the foremost sheet of a stream of lapped sheets while the sameis still partly covered by the rear portion of a sheet being removedfrom the stream and transferred to cylinder 2|.

Other variations in the details of construction of the invention may beemployed. For example the stops 40 instead of rotating about av singlecenter may be secured to continuous bands carried around two centers,these bands being driven with appropriate speed to provide the desiredslowing down operation.

It is known to provide an intermittent rotary transfer mechanism withstops mounted thereon which project into the path of sheets and slowthem down. Such mechanism is employed with sheets fed at high speed inentirely separated condition as distinguished from stream feeding. Suchstops are impractical for use in connection with stream fed sheets forthe reason that a large space between successive sheets is required inorder to permit the stops to pass through the path of the sheets inadvance of their leading edges. It is apparent that by the presentinven- .tion I have provided means for advancing and slowing down sheetsas they approach stationwith stream fed sheets. As shown in Figs. 3 and5 the advancing sheet is much farther along on the feed board than wouldbe the case if slowdown stops were provided on the transfer member andtherefore the sheets are enabled to reach their registering positionearlier in the cycle and longer sheets may be fed. With respect I toFigs. 5 and 7, the stops 40 pass through the r path of the sheet earlierin the cycle than it would be possible for slow-down stops on thetransfer cylinder to do. i I

Having thus described my invention'I claim:

1. In sheet feeding mechanism the combination of a variably moving sheettransfer member and separately mounted mechanism actuatedby variablemovement of said member at a constant speed ratio to control the advanceof sheets thereto.

2. In sheet feeding mechanism the combination of a non-uniformlyrotatingsheet transfer member and separately mounted mechanism actuated byrotation of said member at a constant speed ratio for controlling theadvance of sheets thereto. H

3. In sheet feeding mechanism the combination of variably moving sheettransfer mechanism and separately mounted sheet slowdown mechanismhaving variable movement dependent upon the movement of said transfermechanism.

4. In sheet feeding mechanism the combination of an intermittentlyrotating sheet transfer member having a period of acceleration and one,

of deceleration and separately mounted sheet slowdown mechanism actuatedby rotation of said transfer member during deceleration thereof.

5. In sheet feeding mechanism the combination of an intermittentlyrotating sheet transfer member having a period of'acceleration and oneof deceleration and sheet slowdown mechanism driven at speedproportional to but different from the speed of said member duringdeceleration thereof.

6. In sheet feeding mechanism the combination of an intermittentlyrotating sheet transfer member having a period-of acceleration and oneof deceleration and sheet slowdown mechanism driven at speedproportional to but less than the speed of said member duringdeceleration thereof.

'7. In sheet feeding mechanism the combination of an intermittentlyrotating sheet transfer member having a period of acceleration and oneof deceleration and sheet slowdown mechanism actuated by rotation ofsaid member at speed proportional to but different from the speed ofsaid member during deceleration thereof.

8. In sheet feeding mechanism the combination of an intermittentlyrotating sheet transfer member and means for feeding sheets to aposition of rest where they may be taken by said transfer member, saidmeans being arranged to feed the sheets for at least a portion of theirtravel at variable speed different from the surface speed of saidtransfer member but dependent upon the speed variations of said transfermember. i

9. In sheet feeding mechanism the combination of an intermittentlyrotating sheet transfer member having a period of deceleration and meansfor feeding sheets to a position of rest where they may be taken by saidtransfer memher, said means being arranged to feed the sheets for atleast a portion of their travel at variable speed proportional to butless than the variable surface speed of said transfer member duringdeceleration thereof.

10. In sheet feeding mechanism the combinationof a non-uniformlyrotating sheet transfer member and means for feeding sheets in lappedrelation to said member comprising means operating atvariable speed lessthan the surface speed of the transfer member and dependent upon thvariations in speed of said non-uniformly rotating transfer member.

11. Inmechanism of the class described, a non-uniformly rotating sheettransfer member, sheet stops adjacent thereto, means for advancsheets inlapped relation toward a position of rest against said stops, andslowdown means mounted separately from said transfer member, actuated byrotation of said transfer member, and arranged to engage the foremostlapped sheet and slow the same down before reaching said stops.

12. In mechanism of the class described, a nonuniformly rotating sheettransfer member, sheet stops adjacent thereto, means for advancingsheets in lapped relation toward a position of rest against said stops,and slowdown means having speed dependent upon but less than the sur--face speed of said transfer member during variable rotation thereofarranged to engage the foremost lapped sheet and slow the samedownbefore reaching said stops.

13. In a mechanism of the class described, a uniformly rotating sheetreceiving cylinder, a non-uniformly rotating sheet transfer membercooperating therewith, sheet stops adjacent said transfer member andmeans for advancing sheets in lapped relation to a positionof restagainst said stops including means effective to advance the foremostlapped sheet at a speed proportional to the speed of said transfermember during a portion of the decelerating movement thereof.

14. In mechanism of the class described, means for feeding sheets alonga given sheet path, a

non-uniformly rotating sheet transfer member on one side of said path,sheet stops at the for ward end of said path adjacent said transfermember, and slowdown means mounted on the opposite side of said pathoperatively connected with said transfer member adapted to engage asheet traveling in said path and to move toward the stops at a speedproportional to the speed of the transfer member.

15. In mechanism of the class described, means for feeding sheets inlapped relation along a given sheet path, a non-uniformly rotating sheettransfer member on one side of said path, sheet stops at the forward endof said path adjacent said transfer member, slowdown means mounted onthe opposite side of said path operatively connected with said transfermember adapted to engage the foremost one of said lapped sheets and tomove toward the stops at a speed proportional to but less than the speedof the transfer member.

16. In mechanism of the class described, means for feeding sheets alonga given sheet path, a non-uniformly rotating sheet transfer member onone side of said path, sheet stops at the forward end of said pathadjacent said transfer member, a rotating suction wheel mounted on sheetin said path and to decelerate as the transfer member decelerates.

17. In mechanism of the class described, means for feeding sheets alonga given sheet path toward a position of rest, a non-uniformly rotatingsheet transfer member on one side of said path, a plurality of alignedrotating stops mounted on the opposite side of said path operativelyconnected with said transfer member and arranged to project through saidpath at proper times in advance of a sheet, said operative connectionsbeing such as to cause said stops to move at a speed proportional to butless than the surface speed of the transfer member, whereby each sheetis slowed down as it approaches said position of rest prior to beingtaken by said transfer member.

18. In mechanism of the class described, means for feeding sheets alonga given sheet path toward a position of rest, a non-uniformly rotatingsheet transfer member on one side of said path, a plurality of alignedrotating stops mounted on the opposite side of said path operativelyconnected with said transfer member and arranged to project through saidpath at proper times in advance of a sheet, said operative connectionsbeing such as to cause said stops to move at a speed proportional to butless than the surface speed of the transfer member, whereby each sheetis slowed down as it approaches said position of rest prior to beingtaken by said transfer member, and cam means actuated by said transfermember for rapidly withdrawing said rotating stops as the transfermember is about to move a sheet forward.

19. In mechanism of the class described, means for feeding sheets alonga given sheet path toward a position of rest, a non-uniformly rotatingsheet transfer member on one side of said path, slowdown means mountedon the opposite side of said path operatively connected with saidtransfer member adapted to engage a sheet traveling in said path and tomove in the direction of sheet travel at a speed proportional to thespeed of the transfer member, and sheet smoothers carried by saidtransfer member in advance of the point of engagement thereof with thefront edge of a sheet.

20. In sheet feeding mechanism, the combination of a non-uniformlyrotating sheet transfer member arranged on one side of the sheet path,and means for feeding sheets in lapped relation to said membercomprising stops rotating about an axis located on the opposite side ofthe sheet path at a distance from the sheet path less than the radius ofsaid transfer member, said transfer member and said stops being gearedtogether for one-to-one rotation, whereby said stops are adapted tofunction as slow-downs for sheets moving through said path at a maximumspeed less than the maximum surface speed of the transfer member.

HOWARD A. PRITCHARD.

